Generally, a handheld electronic device, for example, a mobile phone, includes a touch screen assembly, a rear cover, an internal structure support assembly, an appearance part, and so on. Traditional appearance parts and internal structure support assemblies usually are made of high-strength and high-hardness materials like stainless steel or aluminum alloy. Due to the high-strength and high-hardness materials of the appearance part, the appearance part and the internal structure support assembly can be connected only in a screw locking manner or a welding manner. As a result, a mobile phone assembling process is relatively complicated with a high cost.